Rotary interrupter switch



July 20, 1965 H. E. DENNEE RQTABY INTERRUPTER SWITCH Filed April 13. 1961 y m Ina "H United States Patent 3,196,225 ROTARY INTERRUPTER SWITCH Hariey E. Dennee, Flint, Mich., assignor to General Motors Corporation, Detroit, Mich, a corporation of Deiaware Filed Apr. 13, 1961, Ser. No. 102,765 2 Claims. (Cl. Nil-27) This invention relates to a rotary switch, and more particularly, to a rotary switch of the type producing several electrical pulses for each revolution of a mechanical input shaft.

Frequently it is desirable to convert the rotation of a shaft to an electrical signal; for example, to furnish pulses for an impulse type electronic tachometer. The purpose of this invention is to provide a rotary switch of simple construction and small size which will produce several pulses for each revolution of mechanical input rotation, and further to provide a contact for making such a switch possible.

The invention is carried out by providing a contact member having a plurality of integrally connected spring fingers circularly arranged and extending substantially parallel to each other.

The invention is further carried out by providing a switch embodying such a contact and having at east one other electrical contact for coaction with the first said contact and means for causing such coaction.

The above and other advantages of the invention will be made more apparent from the following specification taken in conjunction with the accompanying drawings wherein like numerals refer to like parts and wherein:

FIGURE 1 is a partly broken away elevational view of a rotary interrupter switch according to the invention;

FIGURE 2 is a section taken along lines 22 of FIG- URE 1; and

FIGURE 3 is a developed view of the multi-fingered contact of the switch of FIGURE 1.

The switch comprises a metallic housing generally cylindrical or hexagonal in shape and a cap 12 of insulating material threadedly secured thereto. The end of the housing 10 opposite the cap 12 has a rotatable shaft 14 extending therefrom for connection with an external source of rotation. The shaft 14 extends into the housing 10 through a seal 16 and is journaled within a constricted bearing portion 18 of the housing 14 The upper end of the shaft 14 supports a cam 20 which is secured thereto for rotation therewith. A bossed portion 22 of the housing extends upwardly from the hearing portion 18 of the housing concentric to the shaft 14. A many-fingered contact arrangement 24 generally cylindrical in form fits around the boss 22 and is secured thereto by a retaining ring 26. The fingers 28 of the contact arrangement 22 extend upwardly concentrically with the shaft 14 and beyond the end of the shaft toward the insulating cap 12 and are resiliently biased inwardly. A central projection 31 depending from the insulating cap 12 serves as an abutment for the fingers 28 to prevent them from springing inwardly so far as to continuously ride on the cam 2t). An annular contact member is disposed within the insulating cap 12 so as to be radially spaced from the ends of the fingers 28. A terminal 32 extends through a central opening in the annular contact member 39 and a terminal head 34 engages the underside of the contact 39. The terminal 32 and contact 39 are molded within the insulating cap 12 so that part of the contact 30 is exposed beneath the cap 12 and the terminal 32 extends above the cap 12.

As best hown in FIGURE 3, the contact arrangement 24 is stamped out of a single sheet of material to form a contact having an integral base 36 with several fingers 28 integral therewith. Each of the fingers 28 has near its midpoint a cam follower surface including a pair of cars 38 bent back away from the shaft 14. The extreme tip of each of the fingers 28 is formed into a spherical contact portion 50. Upon assembly of the switch, it is necessary merely to wrap the stamping 24 around the cylindrical boss 22 in the housing It) and clamp a retaining ring 26 therearound. Then, as best illustrated in FIGURE 2, the spring fingers 28 will be so arranged that upon rotation of the shaft 14 the cam 20 will sequentially engage the spring fingers 28 to urge each of them against the inner surface of the annular contact 39, thereby completing a circuit between the housing 10 and the terminal 32. The cam 20 is so shaped that only one finger 28 at a time will touch the contact 36 and that open circuit conditions will exist between the contact periods of successive fingers 28.

In operation, the switch will have its housing 14) connected to ground and its terminal 32 connected to an electrical circuit. When the input shaft 14 is rotated, each of the contact fingers 28 successively make and break electrical contact thereby permitting pulses of current to flow through the terminal 32, contact arrangement 24, and housing It to ground. By connecting an impulse tachometer to the said circuit the rotary speed of shaft 14 may be measured.

The preferred embodiment of the invention described above is merely illustrative of the invention and the scope thereof is intended to be limited only by the following claims.

I claim:

'1. A rotary switch comprising a cylindrical conductive housing, a driving shaft located concentrically within said housing, a cam on said shaft, a unitary contact member, said contact member having a plurality of fingers extending longitudinally along and surrounding said shaft, an external terminal extending into and insulated from said housing, a second contact member, one of the contact members being connected with the housing and the other being connected with the terminal, said second contact member being closely spaced from the said fingers whereby upon rotation of said driving shaft the cam successively engages each of said fingers and moves it into electrical contact with said second contact member.

2. A rotary switch comprising a cylindrical conducr tive housing, a driving shaft located concentrically within said housing, a cam on said shaft, a contact member secured within said housing, said contact member having a plurality of fingers electrically connected to said housing and extending longitudinally along and surrounding said shaft, a cam follower on each of said fingers for cooperation with said cam, a contact area on the end of each finger, an external terminal extending into and insulated from said housing, and an annular contact connected to the terminal, said annular contact being closely radially spaced from the contact areas of said fingers whereby 2 g A} l upon rotation of said driving shaft the cam successively 7 2,650,957 9/53 Cohen 200-466 X engages each of said fingers and moves it into electrical 2,740,870 4/56 Meloni et a1. 200-166 X contact with said annular Contact. 2,824,924 2/ 58' Graybill et al. 200166 X 2,847,522 8/58 Bernard 200166 X References flied y the Examiner 5 2,878,339 9/59 Grashoff et al. 200-8 UNITED STATES PATENTS 3,990,848 5/ 61 Scholz 209-83 1,387,796 8/21 Mason 2G0 19 FOREIGN PATENTS 2,378,294 6/45 Field et a1. 200-27 X 254 793 7 2 Great Britain 2,501,431 3/50 Ausman et al 20027 X 372g gjtgheller 200 27 X 10 BERNARD A. GILHEANY, Primary Examiner. i anto 200-30 2,632,098 3/53 Marchese 200 166 X MAX L. LEVY, ROBERT K. SCI-IAEFER, Exammers. 

1. ROTARY SWITCH COMPRISING A CYLINDRICAL CONDUCTIVE HOUSING, A DRIVING SHAFT LOCATED CONCENTRICALLY WITHIN SAID HOUSING, A CAM ON SAID SHAFT, A UNITARY CONTACT MEMBER, SAID CONTACT MEMBER HAVING A PLURALITY OF FINGERS EXTENDING LONGITUDINALLY ALONG AND SURROUNDING SAID SHAFT, AN EXTERNAL TERMINAL EXTENDING INTO AND INSULATED FROM SAID HOUSING, A SECOND CONTACT MEMBER, ONE OF THE CONTACT MEMBERS BEING CNNECTED WITH THE HOUSING AND THE OTHER BEING CONNECTED WITH THE TERMINAL, SAID SECOND CONTACT MEMBER BEING CLOSELY SPACED FROM THE SAID FINGERS WHEREBY UPON ROTATION OF SAID DRIVING SHAFT THE CAM SUCCESSIVELY ENGAGES EACH OF SAID FINGERS AND MOVES IT INTO ELECTRICAL CONTACT WITH SAID SECOND CONTACT MEMBER. 